<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>let 命令</title>
 <script>
 // 解构默认值
 let [x, y = 'b'] = ['a'];
 console.log(x); //'a'
 console.log(y); //'b'
 </script>
 </head>
 <body></body>
 </html>